Although recent decades have been marked by rapid advances in the treatment of bacterial infections, there have not been comparable advances in the treatment of viral infections. Indeed, today, very few efficacious antiviral agents exist.
Those that are known either suffer from restricted or limited efficacy or are toxic. For instance, amantidine is known to prevent influenza, but must be given prior to infection to be effective. Acyclovir, while often effective in treating herpes virus infections, selects for resistant strains of virus. Also, acyclovir is not effective against many kinds of viruses, including retroviruses and even some herpes viruses, such as cytomegalovirus. Other antiviral agents, such as 3'-azido-3'-deoxythymidine (AZT), are toxic, their activity relying upon a relative, but not absolute, selectivity for viral processes.
Indirectly-acting anti-viral therapies, including interferon and interferon inducers, enhance cellular responsiveness to viral infection, allowing the cells to interfere with the infection process. However, interferon has not fulfilled the promise of early expectations and theory. Interferon inducers are relatively new to the field and their efficacy remains unproven.
Acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC) are caused by human immuno-deficiency virus (HIV-1), a retrovirus. The HIV-1 virus infects immune, neural and other cells of its host. Eventually most people infected with HIV-1 become abnormally susceptible to a variety of serious opportunistic diseases as a result of the immune deficiency caused by the virus.
The current anti-HIV-1 drugs are either not effective or cause undesirable side effects. These drugs include AZT, 2',3'-dideoxy cytidine (ddCyd), interferon (IFN), mismatched double-stranded RNA (dsRNA) and amphotericin B. In particular, AZT, which has shown some promise in the treatment of AIDS, causes very serious side effects, such as bone marrow suppression, in a high proportion of patients. Also, the beneficial effects of AZT have been reported to abate in 12-18 months, and patients get new infections or develop toxic side effects. Chase, "Doctors and Patients Hope AZT Will Help Stave Off AIDS," Wall Street Journal, Apr. 28, 1988, at 14, col. 1.
An illness referred to as "chronic fatigue syndrome" (CFS) has been associated with an active Epstein-Barr virus infection as evidenced by significantly elevated titers of antibodies to the Epstein-Barr viral capsid antigen or early antigen and a deficiency of late-appearing antibodies in many patients suffering from CFS. However, in some patients, Epstein-Barr virus antibody patterns are not definitively abnormal, and some patients are seronegative. Accordingly, other agents may also be involved in the etiology of CFS. These other possible causes of CFS include cytomegalovirus, other viruses, chemical exposure, defects in the immune system, or severe allergies. Center for Disease Contral, Dept. Health and Human Services, Chronic Fatigue Syndrome Mar. 22, 1988 (hereinafter "Centers for Disease Control").
Patients suffering from CFS are chronically, sometimes severely, fatigued. They also show evidence of neurological and immunological dysfunctions.
To date, there is no known effective treatment for CFS. Centers for Disease Control. Several treatment studies are underway using gamma globulin and acyclovir However, a study conducted by the National Institutes of Health indicates that acyclovir is no more effective than placebo in treating this illness. Centers for Disease Control.
Mammalian liver extract has been used for the treatment of a wide range of infectious and noninfectious dermatologic conditions, including acne vulgaris, Journal Invest Dermatology, 2:205-218 (1939); first and second degree burns, Mississippi Valley Medical Journal, 76:199 (1954); sunburn, Clinical Medicine, 3:245 (1956); poison ivy dermatitis, Clin. Med., 3:425 (1956) and Herpes zoster, Southern Medical Journal, 50:1524 (1957). The active principle and mechanism have not been described. Although some medical practitioners have used liver extract for the treatment of dermatologic conditions, it is not regarded as an antiviral or immune modulator agent even for skin therapy.
Mammalian liver extract has been reported to have bradykinin potentiating activity Tewksbury et al., Arch. Biochem. Biophys. (U.S.), 112, 453 (1965); Tewksbury, Archives Int'l de Pharmacodynamie et de Therapie, 173, 426 (1968); Tewksbury, Dissertation Abstracts International-Part II, Vol. 25/04, p. 2214 (1964). Further, one commercially-available liver extract (sold under the trademark KUTAPRESSIN by Kremers-Urban Co., Milwaukee, Wisconsin) exerts its action, according to product literature, only with respect to tissues that have been injured and when inflammation and edema are present.